nifi-stateless/nifi-stateless-bundle/nifi-stateless-engine/src/main/java/org/apache/nifi/stateless/parameter/EnvironmentVariableParameterProvider.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.nifi.stateless.parameter;

import java.util.Map;

public class EnvironmentVariableParameterProvider extends AbstractParameterProvider implements ParameterProvider {
    private final Map<String, String> environmentVariables = System.getenv();

    @Override
    public String getParameterValue(final String contextName, final String parameterName) {
        String envValue = environmentVariables.get(contextName + ":" + parameterName);
        if (envValue != null) {
            return envValue;
        }

        return environmentVariables.get(parameterName);
    }

    @Override
    public boolean isParameterDefined(final String contextName, final String parameterName) {
        return getParameterValue(contextName, parameterName) != null;
    }
}